Comparison of a visiting subspecialist ophthalmology service to Royal Darwin Hospital with interstate transfers: costs and clinical outcomes of treatment

Introduction

Medical and surgical management of patients with eye disease has changed greatly over the past 20 years resulting in improved patient outcomes for both common and rare blinding retinal diseases such as diabetic retinopathy, glaucoma, macular degeneration, corneal disease, uveitis and retinal detachment.¹ A significant cost associated with this better management (and improved outcomes) is the need for a range of fellowship-trained ophthalmologists that practice across the sub-specialties to manage patients with complex blinding eye disease. Accessing this additional specialist workforce is a challenge for patients who live in rural and remote communities.² As an example, it is estimated that less than half of the Aboriginal and Torres Strait Islander peoples who need cataract surgery in the ‘top end’ have access to timely cataract surgery.³

The Department of Ophthalmology at Royal Darwin Hospital (RDH), Australia, adopted a pro-active response to these challenges and for more than 15 years has organised a sophisticated tertiary model of eye care for eye patients. There are 11 ‘fly in-fly out’ (FIFO) consultant ophthalmologists who regularly travel to Darwin to manage patients with complex blinding eye diseases across the various sub-specialties of ophthalmology.

Arguably the highest cost tertiary eye care is that related to vitreo-retinal surgery, which includes surgery for both rhegmatogenous and tractional retinal detachment, and vision-threatening macular diseases such as macular hole, epiretinal membrane and vitreo-macular traction.⁴ Diabetes is a highly prevalent chronic disease in the Northern Territory (NT), which causes complicated traction retinal detachments related to late presentations of diabetic eye disease.^5,6 Such vitreo-retinal disorders need surgery by experienced vitreo-retinal surgeons. Previously such patients were referred to Adelaide or Sydney for surgery. Many Aboriginal and Torres Strait Islander peoples are very reluctant to go ‘South’ because of cultural concerns, safety and environmental issues.^7–10

For patients requiring vitreo-retinal surgery, a sustainable care pathway has been established at RDH whereby consultant vitreo-retinal surgeons from Adelaide and Sydney visit RDH four times per year to manage patients with macular holes, epiretinal membranes, chronic retinal detachments and stable diabetic eye disease locally rather than the patient and their carer flying south to Adelaide or Sydney for a variable period of time. Patients who present with urgent surgical retinal disorders such as macula on retinal detachments and endophthalmitis that require urgent vitrectomy are triaged to fly to Adelaide or Sydney between consultant visits.

The aims of this study were to:

Methods

This study was conducted in accordance with the National Statement on Ethical Conduct in Human Research, and consistent with the principles that have their origin in the Declaration of Helsinki. Approval from the Human Research Ethics Committee of the Northern Territory Department of Health and Menzies School of Health Research was obtained prior to its commencement (reference number 2022-4492).

A retrospective case series of data was collected from consecutive patients presenting to the RDH for vitreo-retinal surgery during the calendar years (1 January–31 December) of 2018 and 2019 – a period prior to the disruptions caused by the COVID-19 pandemic. Two visiting vitreo-retinal surgeons each made four visits to RDH over this period (Fig. 1).

Fig. 1.

Flow diagram of the surgical outcomes recorded for each study group.

Patients were included if they underwent vitreo-retinal surgery in Darwin, or if they were diagnosed in Darwin and transferred interstate for surgery through the transfer model during 2018–2019. The two patient groups are:

All vitreo-retinal surgery was performed as outpatients. These two groups were used to assess both the health economic and clinical outcomes in this paper.

Results

The characteristics of the two study groups are provided in Table 1. The visual outcomes of BCVA, IOP, failure of initial surgery and additional procedures are displayed in Table 2. There was a significant difference in BCVA 6 months post-operatively, with those in the FIFO group having worse BCVA compared to the transfer group. There was also a significant difference in the time of diagnosis to surgery between the two groups with the FIFO group waiting on average 79.98 days and the transfer group only 14.48 days. This difference is due to the transfer group requiring urgent surgical intervention compared to the FIFO group and thus receiving this care in a shorter time following diagnosis.

Table 3 lists the complications and additional procedures. Six of the seven patients with multiple procedures in the transfer group had a combination of removal of oil and cataract surgery. There was no significant difference in the rate of complications (P = 0.0789) or the rate of additional procedures (P = 0.056) between either group.

A summary of the costs and expenditures at different stages of the care pathway is presented in Table 4. The cost of interstate travel includes flights, accommodation and on the ground travel (taxis or ubers) for the transfer group and for the FIFO group is the above costs plus meals and incidentals. The interstate costs for patients to go to Sydney or Adelaide for their treatment was significantly higher in the transfer group, with an average cost of A$1862.41 per patient in the transfer group versus A$597.66 per patient in the FIFO group. There were no ED episodes encountered by the transfer group between their diagnosis and surgery as they were urgently sent for surgical intervention. The cost of outpatient care from diagnosis to surgery was significantly higher in the FIFO group, with an average cost of A$1222.50 compared to A$259.40 in the transfer group. Thus, there were some aspects of the two programs that suggest cost offsetting. All other costs were otherwise analogous between the two groups.

It is important to recognise that all the FIFO consultant ophthalmologists see outpatients in RDH clinics as well as providing surgical care. The FIFO vitreo-retinal surgeons locally managed 291 outpatients with medical retinal diseases at RDH Eye Clinic across their eight visits in addition to the 41 patients that had surgery. Additionally, many of the locally managed surgical patients also had vision-threatening medical retinal disease such as diabetic macular oedema that required ongoing regular review and treatment not related to their vitreo-retinal surgical disorder. Surgical FIFO patients also needed review to prioritise surgery and for post-operative care.

Discussion

This study is the first in Australia to quantify the relevant costs and clinical outcomes for patients receiving sub-specialty directed high acuity eye care via a FIFO model. The findings demonstrate the value of this service and inform local healthcare managers of the value of this model of care. The study confirms that this is a sustainable financial model for providing local high acuity eye care for blinding eye disease. The results are broadly applicable to those in other rural and remote health services.

The main strength is that the study has explored both the health outcomes and costs associated with the FIFO and transfer models and thus can provide an analysis of both the overall health economic impact and individual patient costs. The study demonstrates excellent visual outcomes with similar costs for both care pathways, comparable to previous reports on similar populations.^16,17 Further studies are needed to identify and quantify the psychosocial, cultural and health economic benefits of treatment locally compared to treatment performed interstate.

As the data were collected, it became obvious that the two groups contained quite different retinal disorders. The patient numbers for retinal detachment in both surgical groups were small: there were six patients in the FIFO group compared to 21 patients in the transfer group, and for vitreous haemorrhage there were six patients in the FIFO group and five patients in the transfer group. These numbers are not sufficient for meaningful analysis. The study provides early evidence on the outcomes and costs which, with additional patient cohorts and longitudinal data, can be explored further including disentangling the outcomes and costs to determine the main factors such as personal, health and local/broader health system characteristics.

Australia has the second largest absolute aeromedical retrieval service worldwide and the largest per capita within the 38 nations of the Organisation for Economic Cooperation and Development.¹⁸ Ophthalmology is likely to be a major driver of this, as most of these patients are ambulant and well enough to travel without outside assistance. Restrictions on the use of air travel after surgery involving intraocular gas are well known.¹⁹ The substitution of silicone oil tamponade for gas enables a faster return to home, family and work without the requirement for a prolonged overland journey. The use of intraocular gas would prolong disability, delay the return to work and no doubt increase the direct and indirect costs of care despite the need for secondary surgery.

The transfer group had better vision outcomes but required more procedures to achieve this. The prevalent diagnosis in the transfer group was retinal detachment which needs urgent surgery to optimise visual outcomes. These patients could not wait for a FIFO specialist visit, and were dealt with in the transfer care pathway which has been shown effective elsewhere.²⁰ The significantly worse BCVA outcomes in the FIFO patients at 6 months is most likely due to the different diagnoses between the groups.

Demographically, there was a higher proportion of Aboriginal and Torres Strait Islander peoples in the FIFO group. These patients have strong connections to country and community, and may be more reluctant to transfer interstate for care.^7,8 Being able to manage these patients locally has important social and cultural benefits. Further studies are needed to address the benefits of local care on patient-reported outcomes for eye disease and co-morbidities as well as co-morbidity disease outcomes.

The only significant differences in cost between the FIFO and transfer groups were the costs of interstate travel and outpatient costs from diagnosis to surgery. The OPD diagnosis to surgery (Table 4) includes all OPD visits while waiting for the FIFO consultant to come. As a result it is higher than the transfer group where the patient is transferred rapidly without further OPD visits. Despite additional OPD visits while waiting for the FIFO consultant to visit, the overall average total cost is similar to the transfer group. An average cost of A$1264.75 per patient in interstate travel costs was avoided by FIFO; however, an average cost of A$1222.50 per patient was simultaneously expended by FIFO through OPD diagnosis to surgery. Given that there were no other significant differences in costs between the two programs, and a A$984.50 difference in the average total cost, these results suggest that the costs of care are fairly similar. While there may be no immediate cost advantage for any group, the FIFO group has the advantage of facilitating planned reviews for patients with less surgically urgent, but still significant, vision-threatening ophthalmic conditions. Critically, in addition to the 41 patients that had surgery in the FIFO group, 291 outpatients with medical retinal diseases were seen and managed locally at RDH Eye Clinic by the visiting specialist across eight visits.

In the current study, multiple resource usage (costs) and health outcomes (consequences) were collected for both the FIFO and transfer groups from the health system perspective. Thus, both elements are available and reported in the paper. We note that there are other costs and outcomes from the patient/societal perspective that that are likely to be informative to collect in future studies. On the cost side, there are out-of-pocket costs and productivity losses for patients as well as informal carers (such as family members or friends) who accompany patients to appointments and the surgeries, and on the health outcomes side there is quality of life and wellbeing measures. We would recommend these additional costs and outcomes from the patient/societal perspective be included in future research projects in this area to produce broader economic evidence. Thus, the current study has explored the various cost and outcome items from the health system perspective and reported these in a disaggregated manner – consistent with the intent of this type of analysis.

This study is the first in Australia and internationally to examine the costs and clinical outcomes of an ophthalmology sub-specialty FIFO service at a remote large hospital using costings collected at the micro-level. This approach enabled detailed information on the resources used to be identified, quantified and valued for the FIFO and usual care (transfer) groups. The findings are helpful for healthcare administrators considering how to apply this type of FIFO model in other remote eye clinics or even other surgery-based care in the hospital setting. It also provides timely information on important aspects of translation which could help to develop a broader network for care in this clinical area as well as exploring complementary virtual care options such as telehealth to enhance the model.